In an Ethernet network Ethernet signals and power-over-Ethernet (PoE) may be transmitted over the same communication cable, such as a twisted pair copper cable. In order to supply power to a load coupled to the end of the cable, the supply power can be transmitted over the twisted pair copper cable to a power remote-side unit (RU). The power remote-side unit couples the transmitted power out of the cable and provides the supply power to the load. The power for the remote-side equipment may be coupled in the cable at a central side using a central side unit (CU). The twisted pair copper cable connects the central and the remote units.
To be able to use usual network components for the cable and connectors, standard connectors, such as 8P8C (aka RJ45) connectors, may be used to connect the communication cable to the central side unit and the remote-side unit. This leads to the potential risk that a standard Ethernet device may be directly connected to the output of the central side unit and, thus, is directly connected to the power source. An Ethernet device could be damaged by the output power of the central side unit, if a twisted pair cable which is connected to this device at the remote side is plugged in the output connector of the CU at the central location. Furthermore, if by mistake, for example, an Ethernet switch is plugged in the output connector of a central side unit, the Ethernet switch could be damaged, if the output power of the central side unit is switched on.
It may be an impetus to provide a coupling device to couple a supply power source to a communication cable without the risk to damage a device also coupled to the communication cable. It may also be an impetus to provide a coupling device to couple a load to a communication cable on which a supply power is transferred without the risk to damage the device. It is further desirable to provide an arrangement to supply a supply power via a communication cable without the risk to damage a device coupled to the communication cable by the supply power. Furthermore, it may be desirable to provide a method to supply a supply power via a communication cable without the risk to damage a device coupled to the communication cable by the supply power.